Fuel injection pump for internal combustion engines



A. A. SIDNEY 'Y 1,945,452 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES Jan. 30, T1934.

Filed July 1l, 1952 Patented Jan. 3o, 1934 1,945,452

FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES Arthur Alexander Sidney, Thornton Heath, England, assignor to Bryce Limited, a company of Great Britain Application July 11, 1932, Serial No. 621,957, and

in Great Britain April 4, 1932 1 Claim. (Cl. 103-41) The invention relates to improvements in plunger l. The casing 3 is provided with an pumps for supplying fuel to internal combustion inlet 6 communicating with a, source of fuel for engmes, and more particularly to pumps of the an engine. The upper end of the sleeve. 2 is type in which fuel is drawn or forced into a chamclosed by a steel ball '7 biased' on to a seating ber from which it is expelled to the engine by a formed therein, by a spring 8 housed Within 60 plunger sliding within the chamber. the end of a union member 9 which is screwed The object of the invention is to provide means into the upper end of the casing The biasing -g whereby the amount of fuel expelled from the force exerted by the spring 8 is sufcient to mainchamber may be varied at will. tain the ball '7 on its seating until the pressure 10 According to the invention the plunger is of exterted by the fuel increasessubstantially above 65 constant stroke and is provided with passageits supply value` The union 9 serves to retain the ways communicating at one end with the vchamsleeve 2 in position* axially, and has a bore 10 ber, and co-operating at the other end with one therethrough whereby the chamber' enclosed by or more ports in the walls of the chamber, wherethe upper end of the sleeve 2 and the plunger 1 by fuel is bypassed from the pump during the may be put into communication with a pipe 70 initial and nal portions of the working stroke leading to the engine. of the plunger, and is expelled from the cham- The plunger 1 is drilled axially for a short ber only during the mid portion of the stroke of distance with a hole 11, and two diametral holes the plunger. Further passageways are provided 12 and 13 respectively, each CIOSSHS the 1101 11 in the plunger whereby the fuel may also be byare drilled in the plunger perpendicular to one 75 passed during the intermediate portion of the another. .The diametral hole 13, which is remote stroke. All the passageways in the plunger are from the upper end of the plunger, communicates symmetrically arranged about the axis thereof at its outer end with a circumferential groove so that the plunger is alwaysA balanced. 14 recessed in the plunger.

The plunger is arranged for rotation relatively On the lower end of the plunger 1 is cottered 80 to the ports in the chamber so that the intera guiding member 15 provided with two diametral mediate period of bypassing may be varied and Wings 0r ears 16 and 17 respectively. Which are thus also the Working portion of the plungers arranged to slide within longitudinal slots 18 and stroke. The ports in the chamber are conven- 19 respectively cut in a bushing 20. This bushing iently of triangular form and may co-operate is mounted for rotation within a projecting boss 85 with circular cross-sectioned passageways in the 21 formed in the casing 3 and is secured from pump plunger. The rotation of the plunger may axial movement by means of a radially disposed be effected from the exterior of the pump so that screw 22, the 'inner end of which engages a cirthe variation of output ofl the pump may be cumferential slot 23 in the bushing 20- The controlled at will in a simple and efficient manner. bushing is provided With a' plurality 0f l0ngitudi- 90 A preferred embodiment of the invention is nal teeth 24 which are engaged by teeth in a rack illustrated by way of example in the accompanymember 25 slidably. mounted for longitudinal ing drawing in whichzmovement in the casing 3. The movement of Figure 1 shows in vertical sectional elevation, this rack can be initiated and controlled from the a ful pump according to the'invention, exterior of the casing and provides suitable means 95 Figs. 2, 3 and 4 are detailed views showing for rotating the plunger 1 about its axis Without the pump plunger in different positions of its affecting the reciprocating motion thereof.

stroke, The sleeve 2 within which the plunger 1 is dis- Fig. 5 is a fragmentary view of a sleeve mernposed is provided with an'external circumferenber incorporated within the pump, and tial groove 26, and two oppositely disposed ports 100l Fig. 6 is an enlarged view of a portion of this 27 are provided in said sleeve and communicate sleeve showing relative positions of a passagewith said groove 26. The ports are substantially Way in the plungerV with respect to a port in the triangular in cross-section as shown in Fig. 5. sleeve. The diametral hole 12 within the plunger 1 is Referringfto the drawing, the pump consists spaced from the upper end oi the plunger such 105 essentially of the plunger 1, which is mounted that the distance from its upper edge to the end for reciprocation within a sleeve 2. The sleeve of the plunger is less than the greatest depth of is secured in a casing 3, in the lower end of the port- 27. The position of the groove 14 is arwhich is housed a cam 4, which operates atappet ranged so that the distance of its upper edge 5 to produce the reciprocating motion of the from the lower edge of the diametral hole 12 is 110 also less than the greatest depth of the port 27. The plunger 1 is arranged relatively to the sleeve 2 so that at the lower end of its stroke, the upper end of the plunger is substantially in alignment with the lowest edges of the ports 27, and at the upper end of its stroke, the lower edge of the groove 14 is still below the upper edges of the ports 27.

When the centre line of the hole 12 is in alignment with the centre line of the ports 27 as shown at 12 in Fig. 6, no fuel passes to the engine because during the upward stroke of the plunger, the fuel in the chamber bounded by the sleeve 2, the ball 7 and the top of the plunger 1 is rst returned to the conduit 6 across the top of the plunger until this top passes above the upper edges of the por-ts 27 as shown in Fig. 2, then the fuel passes by way of the axial hole 11 and the diametral hole 12 until the lower edge of the hole 12 passes the upper edges of the ports 27 as shown in Fig. 3, and nally it passes by way of the axial hole 11, the diametral hole 13 and the groove 14, as shown in Fig. 4, the-'upper edge of the groove 14 reaching the lower edge of the ports 27 just as the lower edge of the diametral hole 12 passes the upper edges of these ports as shown in Fig. 3.

When the plunger is rotated so that the outer ends of the diametral hole 12 do not pass across the ports 27 at all, as indicated at 12 in Fig. 6, the pump operates to expel the maximum quantity of fuel, this quantity being pumped during the upward passage of the plunger from the point in its stroke when its upper edge passes the upper edges of the ports 27 to the point where the upper edge of the groove 14 reaches the lower edges of the ports 27. These two extreme positions of stroke are shown respectively in Figs. 2 and 3, and are situated in the mid portion of the complete stroke of the plunger, so that the pumping operation takes place during the period when the plunger is travelling at its highest velocity.

By rotating the plunger so that the ends of the diametral hole 12 pass across the inclined edges of the ports 27, as shown at 12"' in Fig. 6, the quantity of fuel being pumped may be varied in a convenient manner from a minimum of zero at 12 to a maximum at 12", the delivery always sov occurring during the mid portion of the plungers stroke.

It will be seen that owing to the construction and arrangement of the constituent parts of the pump, a plunger of symmetrical form may be obtained, the balance of which is not affected by rotation about its longitudinal axis. This feature in combination with the arrangement whereby the pump plunger which is of constant stroke only delivers fuel during the mid portion of its stroke, enables an exact predetermined quantity of fuel to be delivered, andv also enables this quantity to be controlled within very exact limits.

A fuel injection pump for internal combustion engines, comprising a cylinder having a diametrally opposed pair of substantially triangu- 3 lar ports for connection at their outer ends with a source of fuel, each of said ports having one of its edges disposed obliquely to the axis of said cylinder, and a plunger adapted to be reciprocated with constant stroke in said cylinder to move its active face inwardly and outwardly beyond said ports, said plunger having a circumferential groove spaced from its active face a distance greater than the maximum dimension of said ports longitudinally of said cylinder and an axial bore extending. from its active face to a point between its ends and communicating with said circumferential groove, said plunger also having between its active face and said groove a diametral hole communicating with said axial bore, the edge of said diametral hole nearest the active face of said plunger being spaced fromsaid face an the edge of said circumferential groove nearest said diametral hole being spaced from said hole a distance less than the maximum dimension of said cylinder ports longitudinally of said cylinder, the circumferential groove of said plunger being adapted to communicate with the ports of said cylinder during the final portion of the instroke of said plunger for by-passing fuel from said cylinder and said plunger being rotatable about its axis to adjust said diametral hole relatively to the oblique edges of said cylinder a.,

ports. v p

ARTHUR ALEXANDER SIDNEY. 

